Piston for internal-combustion engines.



0. DAY & G. E. WINDBLER. PISTON FOR INTERNAL COMBUSTION ENGINES.

APPLIUATION FILED JUNE 13, 1912.

Patented Mar. 10, 1914.

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UNITED STATES PATENT OFFICE.

CHARLES DAY AND GEORGE E. WINDELER, OF STOCKPORT, ENGLAND, ASSIGNORS TOGENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

PISTON FOR INTERNAL-COMBUSTION ENGINES.

Specification of Letters Patent.

Patented Mar. 10, 1914.

Application filed June 13, 1912. Serial No. 703,396.

To all whom it may concern Be it known that we, CHARLES DAY and GEORGEE. WINDELER, subjects of the King of Great Britain, residing atStockport, county of Cheshire, England, have invented certain new anduseful Improvements in Pistons for Internal-Combustion Engines, of whichthe following is a specification.

The present invention relates to pistons for internal combustionengines, and in particular to engines operating on the constant pressureplan where crude oil is used as a fuel. In such engines it is desirableto provide the pistons with removable heads so that, when injured by theheat to which they are subjected, they can be replaced. It is alsonecessary in order to reduce the weight of these removable heads andtoprovide for the conduction of heat from the top face of the piston tothe cylinder wall, to core them out, thus forming chambers. Because thehead is removable a joint is necessary between it and the body of thepiston. From practical experience we have found that the lubricating oilwhich lies on the cylinder wall in the form of a thin film, is forcedthrough this joint and enters the cored chamber or chambers in the headwhere it rapidly accumulates and is carbonized, forming a hard compactmass. This mass is of course kept at a high temperature in the head andundoubtedly interferes with the transmission of heat to the cylinderwalls where a large part of it is absorbed by the cooling water. Afterthe chambers have become filled with carbon, the said heads crack orsplit and therefore have to be replaced. The carbon retards thedissipation of heat from the bot center to the side Walls of the headwhich are cooled by the water chamber.

in the cylinder, and in our opinion, since the carbon is very hard, itprevents the free contraction of the casting, the action being similarto the effect caused in a mold when a hard baked core is used. \Vhetherthis be the true explanation or not, the fact remains that the heads docrack and split and consequently have to be renewed at considerableexpense and loss of time. I

We have discovered a means for preventing the lubricating oil fromworking into the joint between the head and the main body of the piston,thereby overcoming the objectionable cracking or splitting of the heads,and said means forms the subject matter of this application.

In the accompanying drawing which illustrates one of the embodiments ofour invention, Figure 1 is a longitudinal section of a piston, and Fig.2 is a detail section of the removable .head.

3 indicates the main body of the piston,

and. 4 the cylinder therefor. The body is provided with an internalflange 5 that is finished on its upper surface and is provided with ashoulder 6 that serves to center the removable head 7. The head isrecessed to receive the projecting shouldered portion of the body. Theparts are united by stud bolts 8, the nuts of which are accessible fromthe underside. The nuts are provided with grooves 9 to receive cotterpins to prevent them from turning after being properly seated. The headis relatively massive in order to withstand the strain to which it issubjected on the firing stroke of the engine. It is also provided with amember 10 that serves to convey heat from the center of the head to itsperiphery and to the main body. Surrounding the member 10 is a chamber11 that is cored out at the time the head is cast. This chamber is forthe purpose of decreasing the weight of the head and is open on itsunderside so that the cored material can be entirely removed. The end oropening of the chamber terminates in the plane of the joint between thehead and the main body. The joint between these parts is made ascarefully as possible. but unless means are provided to prevent it,lubricating oil will work through the joint between the parts and becollected in the chamber 11 where it will carbonize and ultimately causethe head to crack or split. These means will be described later.

In order to reduce the transmission of heat from the head to the pistonpin which passes through the wall 12, a body of asbestos or other heatinsulating material 13 is packed into the head and confined by a plate14. This plate is let into a shouldered recess in the head and isretained by screws 15. These screws are covered by the flange 5 so thatthey cannot work loose when the piston is in operation.

Both the main body and the head are provided with suitable. packingrings 10, some of which are located above and the remainder below thejoint between the-head and the body. These rings, as the piston movesdownward, scrape a certain amount of lubricating oil from the cylinderwall, which oil is discharged at the bottom into an annular groove 17,the latter communicating by a passage 18 with the inside of the body.This arrangement serves to prevent lubricating oil from being forced bythe packing rings into the combustion space 19 at the top of thecylinder.

Referring now to the means for preventing lubricating oil from workingthrough the joint into the chamber 11, a small annular space or passage20 is left between the bottom surface of the head and the upper surfaceof the body. This is in constant communication with a small annulargroove 21 formed in the upper face of the body. Communicating with thisgroove'are axial extending passages 22 which communicate with thehorizontal passages 18 opening into the space within the piston body.The piston ring located above the joint will, on the downward movementof the piston, scrape lubricating oil from the wall of the cylinder, andsaid oil will-flow through the annular passage 20, groove 21- andpassages 22 and 18 to the interior of the body where it does no harm.Said oil will not follow the closely fitting joint between the head andbody because it will take the path of least resistance which is formedby the passages aforesaid. 0n the upward movement of the piston the ringbelow the joint acts as a scraper and forces the lubricating oil intothe passage 20 from which it readily escapes. For convenience thepassages and the holes 22 are drilled from the top to intersect thehorizontal passages 18, but if desired they can be extended directlyinto the space within the body.

Practical experience has demonstrated that the arrangement specifiedwill successfully prevent the entrance of lubricating oil into. thechamber 11 and the damage incident thereto.

In accordance with the provisions of the patent statutes we have setforth what we elieve to represent the best embodiment of-our invention;but it is to be understood that the drawing is onl that our inventioncan e carried out by illustrative, and

other means.

. What we claim as new and. desire to secure by Letters Patent of theUnited States is I 1. A piston comprisin a body portion, a removablehead theror, the joint be tween the parts being perpendicular to theaxis thereof, and means for conveying lubrieating. oil that enters thejoint to the interior of the body portion.

2. A piston comprising a body portion, a I

mounted on the piston above and below the joint between the body portionand head, and a passage that communicates with said joint, receiveslubricantand discharges it into the interior of the body.

4. A piston comprising a body portion, a removable recessed head mountedthereon, a body of heat insulating material located in the recess .toreduce the transmission of heat from the head to the piston pin, and aplate which holds the insulating material in place, the peripheral edgeof which is located in the joint between the body and head.

5.. A piston comprising a body portion having an inturned flange, aremovable chambered head thatengagcs the flanged end of the body, saidhead and flange acting as a means to close said chamber on one side, amember forconveying heat from the head to the body, means for unitingthe head and body, an annular peripheral groove located between the headand body, a passage connecting said groove with the interior of thebody, and packing rings 10- cated on opposite sides of the groove andacting to force lubricant into the groove from which it is conveyed bythe passage into the interior of the body.

6. A piston comprising a body portion, a removable chambered headtherefor, said body acting to close the chamber on one side, packingrings in the body and also in the head, an annular groove located at thejoint between the body and head and between packing rings, a passagereceiving lubricant from the groove and conveying it to the interior ofthe bod and a second annular groove located be ow the packing rings onthe body which receives lubricant and discharges it into said passage.

In witness whereof we have hereunto set our hands and seals this 23rdday of May, 1912.

CHARLES DAY. a 8. GEORGE E. WINDELER. [L.'s.] lVitnesses;

ALEX. F. MACDONALD, JOHN W. GILL.

